/*
 * Copyright (C) 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.emay.sdk.util.json.gson.internal.bind;

import java.io.IOException;
import java.lang.reflect.Array;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

import cn.emay.sdk.util.json.gson.Gson;
import cn.emay.sdk.util.json.gson.TypeAdapter;
import cn.emay.sdk.util.json.gson.TypeAdapterFactory;
import cn.emay.sdk.util.json.gson.internal.$Gson$Types;
import cn.emay.sdk.util.json.gson.reflect.TypeToken;
import cn.emay.sdk.util.json.gson.stream.JsonReader;
import cn.emay.sdk.util.json.gson.stream.JsonToken;
import cn.emay.sdk.util.json.gson.stream.JsonWriter;

/**
 * Adapt an array of objects.
 */
public final class ArrayTypeAdapter<E> extends TypeAdapter<Object> {
	public static final TypeAdapterFactory FACTORY = new TypeAdapterFactory() {
		@SuppressWarnings({ "unchecked", "rawtypes" })
		@Override
		public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> typeToken) {
			Type type = typeToken.getType();
			if (!(type instanceof GenericArrayType || type instanceof Class && ((Class<?>) type).isArray())) {
				return null;
			}

			Type componentType = $Gson$Types.getArrayComponentType(type);
			TypeAdapter<?> componentTypeAdapter = gson.getAdapter(TypeToken.get(componentType));
			return new ArrayTypeAdapter(gson, componentTypeAdapter, $Gson$Types.getRawType(componentType));
		}
	};

	private final Class<E> componentType;
	private final TypeAdapter<E> componentTypeAdapter;

	public ArrayTypeAdapter(Gson context, TypeAdapter<E> componentTypeAdapter, Class<E> componentType) {
		this.componentTypeAdapter = new TypeAdapterRuntimeTypeWrapper<E>(context, componentTypeAdapter, componentType);
		this.componentType = componentType;
	}

	@Override
	public Object read(JsonReader in) throws IOException {
		if (in.peek() == JsonToken.NULL) {
			in.nextNull();
			return null;
		}

		List<E> list = new ArrayList<E>();
		in.beginArray();
		while (in.hasNext()) {
			E instance = componentTypeAdapter.read(in);
			list.add(instance);
		}
		in.endArray();
		Object array = Array.newInstance(componentType, list.size());
		for (int i = 0; i < list.size(); i++) {
			Array.set(array, i, list.get(i));
		}
		return array;
	}

	@SuppressWarnings("unchecked")
	@Override
	public void write(JsonWriter out, Object array) throws IOException {
		if (array == null) {
			out.nullValue();
			return;
		}

		out.beginArray();
		for (int i = 0, length = Array.getLength(array); i < length; i++) {
			E value = (E) Array.get(array, i);
			componentTypeAdapter.write(out, value);
		}
		out.endArray();
	}
}
